MiRNA-200c-3p Promotes Endothelial To Mesenchymal Transition And Neointimal Hyperplasia In Artery Bypass Grafts

Background: Increasing evidence has suggested a critical role for endothelial to mesenchymal transition(EndoMT)in normal embryonic development and a variety of pathological conditions.microRNA-200c-3p(miR-200c-3p)has been implicated in a similar process,epithelial-to-mesenchymal transition.However,its role in EndoMT and post-angioplasty restenosis remains elusive.Objective: To investigate the functional role of miR-200c-3p in EndoMT and neointimal hyperplasia in artery bypass grafts.Methods and Results: miR-200c-3p has been identified as one of the most up-regulated miRNAs during EndoMT by customised miRNA PCR array.miR-200c-3p inhibition prevents EndoMT as evidenced by increased expression of endothelial genes,decreased expression of mesenchymal genes,and reacquired endothelial cell(EC)morphology and function,respectively.Meanwhile the opposite was observed following miR-200c-3p overexpression.Proteomics analysis and luciferase activity assays revealed that Fermitin Family Member 2(FERM2)is the functional target of miR-200c-3p during EndoMT.FERM2 gene inactivation recapitulates theeffect of miR-200c-3p overexpression on EndoMT,and the inhibitory effect of miR-200c-3p inhibition on EndoMT was reversed by depletion of endogenous FERM2 gene expression.Further mechanistic studies revealed that FERM2 suppresses smooth muscle cell(SMC)gene expression by preventing serum response factor(SRF)nuclear translocation,while it prevents EC mRNA decay by interacting with Y-box binding protein 1.In a model of aorta grafting and EC lineage tracing,we observed that miR-200c-3p expression was dramatically up-regulated in grafted arteries,and that EndoMT contributed to neointimal hyperplasia in grafted arteries.miR-200c-3p inhibition in grafted arteries significantly up-regulated FERM2 gene expression,thereby preventing EndoMT and reducing neointimal formation.Importantly,we found a high level of EndoMT in human femoral arteries with atherosclerotic lesions,and that miR-200c-3p expression was significantly increased,while FERM2 expression level was dramatically decreased in diseased compared to healthy femoral human arteries.Conclusions: We have documented an unexpected role for miR-200c-3p in EndoMT and neointimal hyperplasia in grafted arteries.Our findings offer a novel therapeutic opportunity for treating vascular diseases through specific targeting miR-200c-3p/FERM2 regulatory axis.